In FY2012 the entire Entertainment and Devices Division generated $364 million in operating income, only part of it from X-Box (nor is X-Box consistently profitable).

Uh, no.
XBOX is the revenue generator in that division--their online efforts (Bing, ad sales, etc) are the sinkhole eating up XBOX revenues. XBOX generates north of a billion in profits by itself.

Nonetheless, $364 million net profit is about as much as Nintendo makes in a good year.
More than Amazon itself nets, too.

There aren't many business that will clear you $3-5 billion in annual profits no matter who you are. For that matter, there aren't many million-dollar-a-day business, either. But building a few of the latter is relatively "easier" than hitting a jackpot with a much bigger cash cow. Those are few and far between.